Developing Tablet Games with Multiple Physical Objects?

How can we develop for multiple physical toys on the tablet without patent infringements? I can not even find the patent number anywhere on the web. Disney Appmate has so many of them.

We get requests to develop Unity games with physical toys. Basically to have multiple physical objects you need have a conductive material with 3 prongs that are spaced differently (to identify individual physical objects)

At time 8:08 it explains how it works and mentioned a patient. http://www.youtube.com/watch?v=quDUzyFqQwY&NR=1&feature=endscreen

Is there a way to develop for multiple physical objects on the tablet?? Or is all that development not legally possible??